1. Field of the Invention
The present invention relates to a system capable of regulating the engine speed.
2. Description of the Prior Art
Heretofore, in order to prevent decrease of the engine speed caused by imposition of an engine load such as an electric load or the like during idle running of an engine, there has been adopted a method wherein a decrease of the engine speed is compensated by feedback control of the engine speed during idling, or a method wherein a decrease of the engine speed is compensated by increasing the throttle valve opening by a predetermined amount interlockedly with on-off of an electric load or the like to enhance idling.
However, in the former method, it is necessary to ensure stability of the feedback control and this requirement causes a limit in point of response characteristic; besides, in the case of an engine which undergoes a great decrease in its speed under load, a decrease of the engine speed and an increase of vibration during a response delay period cause serious problems.
In the latter method, although the response characteristic is good, since variations in the throttle valve opening are fixed values, there occurs the case where the amount of change in opening is too large or too small for an electric load or the like imposed, thus making it difficult to obtain an optimum engine speed matching the imposed load.